Automotive air conditioning systems often need to be recharged with refrigerant. To recharge, hoses are coupled to an air conditioning system by way of fittings. The hoses typically couple the air conditioning system to a service unit. The service unit contains a supply of refrigerant, as well as pressure gauges and valves for controlling the flow of refrigerant.
The fittings in an automobile can be difficult to couple hoses to. The fittings are typically threaded and the hoses are provided with nuts that are screwed onto the fittings. Many engine compartments are cramped, with the fittings located in hard to reach places. It can be difficult to thread a nut onto a fitting, which nut is on the end of a hose, especially in a cramped location. Frequently, only one hand can be used.
In the prior art, one type of coupling that alleviates some of the problems associated with coupling to a fitting in a cramped place is a bent barb coupling shown in FIG. 1. One end of the hose is connected to the barbed section. The nut is threaded onto the fitting of the air conditioning system. The barbed section is angled about 45 degrees from the nut section. This bent coupling eases the connection of the hose to a fitting in many instances.
The prior art bent coupling suffers from many disadvantages. For instance, when the nut on the coupling is tightened, the hose may twist and kink. This is caused by the end of the hose rotating with the nut. Untwisting the hose is difficult, especially in a cramped space. Furthermore, the hose may be at an awkward angle, pointing away from a desired path. To reorient the hose, the nut be loosened, and the hose angle adjusted. Loosening the nut causes some refrigerant to escape into the atmosphere. It is widely believed that refrigerants cause damage to atmospheric gasses.
Manufacturing the prior art bent coupling presents problems as well. The passageway through the center of the coupling is difficult to machine on center. Also, the coupling is machined in a straight configuration. After being machined, it is bent to form the angle. Bending the coupling requires the coupling to be heat treated (900 degrees Fahrenheit for one hour), followed by a bright dip operation. Bright dipping utilizes copper sulfate, which presents disposal problems due to environmental concerns (copper sulfate is a heavy metal). Furtherstill, bending the coupling can cause failure of the coupling. About 5-10% of the couplings that are bent crack and leak. These cracks are usually detected at the final check of the couplings. These couplings must be thrown away. Sometimes, the cracks manifest themselves after the final check and during operation.